This invention relates to a process and apparatus for the production of paper products, such as moisture absorbing products or a combustible paper fuel.
In the case of a moisture absorbing product, such may be capable of absorbing liquids without losing its shape, and in particular, but not exclusively, such a product in a pelletised form. One embodiment of the invention has been particularly developed for use as xe2x80x9ccat litterxe2x80x9d, although it may be used for other purposes where its moisture absorbing properties are required.
The major products presently available for use as xe2x80x9ccat litterxe2x80x9d or for other moisture (liquid) absorbing purposes, are formed from clay based materials and are non-organic with the resulting problem that they will not decompose. In addition they have the added disadvantage of depositing clay powder on the paws of cats which is subsequently transferred to floor surfaces leaving tracks. In addition such products result in the continued use of mineral resources whilst more recently certain cultivated pasture crops have been unnecessarily harvested and used merely for the purposes of xe2x80x9ccat litterxe2x80x9d.
In the case of paper fuel it may be composed of a relatively high percentage of paper. Whilst paper combusts readily it cannot be used in its basic form as it either burns too quickly in its loose sheet form or will not burn satisfactory when in the form of a thick mass. In addition, it is important to consider the physical transportation of recyclable paper in its normal form from collection zones to points of use for heating and/or cooking.
As a result of a heightening of community awareness, the supply of paper for recycling has increased to such a degree that it, in many cases, far exceeds the demand for conventional products made from such recycled paper, and as a result the excess is disposed of by landfilling or exported usually at the cost of the country.
In international patent application no. PCT/AU91/00308 (Publication no. WO92/01833) there is disclosed a process and an apparatus for the production of paper products, such as xe2x80x9ccat litterxe2x80x9d or paper fuel, comprising reducing paper to a particulate form by shredding and grinding, conveying the particles of paper as a layer on a first conveyor firstly beneath a first levelling and compacting roller and thereafter beneath a first set of water sprays, before discharging from the conveyor onto a second conveyor through a rearwardly inclined transfer chute to invert the layer during transfer. The inverted layer on the second conveyor passes firstly beneath a second levelling and compacting roller and thereafter beneath a second set of water sprays. The paper product is completed by extruding the paper and water mixture and cutting the extruded mix into pellets before subjecting the pellets to dehydration. In the case of paper product to be used as paper fuel, the paper is mixed with coal dust.
The process and apparatus referred to above has proved effective for the production of paper products, but some difficulties have been encountered in firstly controlling the discharge of the shredded and ground particulate paper from a supply bin or hopper onto the first conveyor, and secondly in forming at the end of the process a suitably compacted or compressed paper and water mixture for extrusion and subsequent cutting into pellets.
It is therefore an object of a first aspect of the present invention to provide a process and apparatus for controlling the discharge of shredded and ground particulate paper from a bin or hopper onto a conveyor.
It is also an object of a second aspect of the present invention to provide a process and apparatus for compacting or compressing a paper and water mixture on a conveyor for extrusion and subsequent cutting into pellets.
According to the first aspect of the invention there is envisaged a process for producing a paper product, including the steps of reducing paper to particulate form, mixing the particles of paper with water, subjecting the mix to pressure on a conveyor to form a compacted mass layer which is subsequently subjected to dehydration to reduce the moisture content, before or after the cutting thereof into pellets, wherein the paper in particulate form is discharged from a bin or hopper onto the conveyor on which it is to be mixed with water, and wherein the paper in particulate form while being discharged is subjected to both agitation and even distribution across the width of the conveyor.
The first aspect of the present invention also envisages an apparatus for carrying out the process defined above.
According to the second aspect of the invention there is envisaged a process for producing a paper product, including the steps of reducing paper to particulate form, mixing the particles of paper with water, subjecting the mix to pressure to form a compacted mass which is subsequently subjected to dehydration to reduce the moisture content, wherein the subjection of the mix to pressure to form a compacted mass is, or includes, wrapping a conveyor laterally over itself and around the mix to envelope and compact the mix prior to dehydration.
The second aspect of the invention also envisages an apparatus for carrying out the process defined above.
The invention still further envisages a paper product resulting from the process and apparatus of the first and second aspects of the invention defined above.